Faraday Shield Temperature Control via TCP Coil Heating
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Solution Overview
Problem
In semiconductor manufacturing, particularly during the production of magneto-resistive random access memory (MRAM), non-volatile etch products like ruthenium, molybdenum, and titanium deposit on the interior surfaces of plasma process chambers, including the faraday shield, leading to thermal cycling and potential particle generation that can interfere with wafer chucking and circuitry, reducing yield.
Innovation Solution
A method to control the temperature of the faraday shield by applying power to the TCP coil under specific plasma limiting conditions during wafer transfer and autocleaning operations, maintaining the temperature within a stable range to minimize thermal cycling and particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the faraday shield temperature is allowed to drop during wafer transfer operations, then energy consumption is reduced, but thermal cycling increases causing particle generation that reduces manufacturing precision
Solution Approach 1:
The patent applies periodic heating cycles to the faraday shield, where heating is activated during wafer transfer operations to prevent excessive temperature drops, and then deactivated during plasma processing when heating is not needed. This periodic action maintains temperature stability during critical operations while reducing overall energy consumption during non-critical periods.
Solution Approach 2:
The patent dynamically adjusts the heating power parameter based on operational phase, applying higher power during wafer transfer to minimize thermal cycling and particle generation, then reducing or eliminating heating during plasma processing. This parameter change strategy balances energy consumption with manufacturing precision requirements.
2Manufacturing precision
If the faraday shield temperature is maintained stable during wafer transfer, then particle generation is reduced, but energy consumption increases
Solution Approach 1:
The heating system operates periodically rather than continuously, activating only during wafer transfer operations when thermal stability is critical to prevent particle generation, and deactivating during plasma processing when the plasma itself maintains adequate temperatures. This periodic operation achieves manufacturing precision goals while minimizing energy consumption.
Solution Approach 2:
The heating is applied in advance during wafer transfer operations before particle generation could occur, preventing temperature drops that would lead to particulate formation. This preliminary action during critical phases prevents quality issues while avoiding continuous heating that would waste energy.
3Stability of the object's composition
If heating is applied continuously to the faraday shield, then thermal cycling is minimized, but plasma processing uniformity deteriorates
Solution Approach 1:
The heating is applied periodically during wafer transfer operations to minimize thermal cycling and particle generation, then stopped during plasma processing to maintain plasma uniformity. This periodic application strategy achieves thermal stability when needed without compromising plasma processing quality.
Solution Approach 2:
The heating function is extracted from continuous operation and applied only during specific non-plasma phases (wafer transfer), separating the thermal stabilization function from plasma processing. This extraction allows plasma processing uniformity to be maintained while still achieving thermal stability during critical transfer operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces thermal cycling of the faraday shield, thereby minimizing particle generation and maintaining process chamber cleanliness, which enhances the reliability and yield of semiconductor manufacturing.
Implementation Method 1
applying power to a TCP coil under a plasma limiting condition
Implementation Method 2
A plasma contains various types of radicals, as well as positive and negative ions
Implementation Method 3
a chamber coil performs a function analogous to that of a primary coil in a transformer, while the plasma performs a function analogous to that of a secondary coil in the transformer
Data Source
AI summary
A method for controlling thermal cycling of a faraday shield in a plasma process chamber is provided. The method includes: performing a first plasma processing operation on a first wafer in the plasma process chamber; terminating the first plasma processing operation; performing a first wafer transfer operation to transfer the first wafer out of the chamber; and, during the first wafer transfer operation, applying power to a TCP coil under a plasma limiting condition.